Mechanical press convertible in respect to compression or tension drive and length of stroke



w. KLOCKE 2,491,317 MECHANICAL PRESS CONVERTIBLE IN RESPECT TO COMPRESSION Dec. 13, 1949 OR TENSION DRIVE AND LENGTH 0E STROKE Filed Jan. 21, 1947 F! G. I

INVENTOR.

WILLIAM KLocKE m mrw ATTORNEY.

Patented Dec. 13, 1949 UNITED STATES PATENT OFFICE MECHANICAL PRESS CONVERTIBLE IN RE- SPECT T COMPRESSION OR TENSION DRIVE AND LENGTH OF STROKE 2 Claims.

This invention relates to mechanical presses and provides improvements therein.

The invention provides a crank-driven mechanical press which is convertible to and from a press in which the force which drives the reciprocating tool-carrying slide on its working The invention further provides a mechanical press of the knuckle-joint type having the characteristics set forth above, and capable of relatively long adjustments of the slide at its bottom-of-the-stroke position and capable of stripping, on the return stroke of the slide, tools from work which clings tenaciously to the tools.

The advantages of the invention are that a large economy is eifected in the manufacture of presses and that the press user can obtain the performance of a number of presses with a single press. Press manufacturers can meet the specifications of customers for a press in which the driving force is applied on the working stroke of the slide under compression or under tension with one set of parts for any given size press. He can meet customers specifications of length of stroke of slide also with one set of parts, one part, a simple rocker being left partially unfinished and holes for a wrist-pin being bored to conform to the length of stroke desired after an order is received.

The press, being of the knuckle-joint type, imparts a slow end-movement to the slide on its working stroke; this enables metal and plastics being worked to conform well to the shape to be imparted thereto by dies, and conserves the dies, the dies ordinarily having about three times the life which they would have in an ordinary crank-press.

For plastics work, a press with a slide having a slow end-movement is highly desirable.

The press arranged for application of the driving force to the slide under tension, also contributes to the conservation of the dies, and is highly preferred, if not necessary, when the press break when an excessive resistance is encountered by the slide, and thereby save other more expensive press parts. I

An embodiment of the invention is illustrate in the accompanying drawings, wherein:

Fig. 1 is a side elevation of said embodiment of press with parts in section;

Fig. 2 is a front elevation thereof;

Fig. 3 is a vertical sectional view of the operating parts of the press, the rocker being shown in a reverse position to that illustrated in Fig. 1;

Fig. 4 is a view of the rocker in side elevation;

Fig. 5 is a diagrammatic view illustrating the movements of the press slide and its driving mechanism;

Fig. 6 is a diagram illustrating the movement of the slide through one press cycle, and also illustrating the movement of the slide of a conventional crank press.

Referring to said drawings, numeral in designates the press frame, numeral I2 the bed, and numeral M the slide. Tools (not shown) are mounted on the bed and slide.

The slide actuating mechanism comprises a crank shaft 16 having a crank l'l thereon, driving rod 19, a rocker 2| and a connecting rod 23. The crank shaft is driven in a suitable manner, as by means of a fly wheel 25 mounted thereon, and a motor and belt, not shown.

The rocker 2| has an arm 21 which is pivotally connected to the connecting rod 23 as by means of the pin 36. The rocker has a second arm 32 which is connected to one end of the driving rod l9 as by means of a pin 34.

The rocker is pivotally mounted in the press frame in line with the press slide 14 by means of journals 36.

The connecting rod 23 is of adjustable form, a conventional form being shown, comprising two parts, one of which has a ball 38 thereon, forming part of a ball and socket connection with the slide, and having a threaded connection 40 with the other part of the connecting rod. The adjustable connecting rod enables the position of the slide in its bottom-of-the-stroke position, to be adjusted toward or away from the bed l2. The adjustable connecting rod not only provides for adjustment at the bottom-of-thestroke position of the slide, but also provides a firm connection through which driving force may be applied on the return stroke of the slide, to separate work which clings to a punch or other tool carried by the slide.

The driving rod I9 is advantageously provided with a journal cap 43, attached to the driving rod, around the crank IT, by means of bolts 44. By using bolts which have a yield-point which is less than the yield-point and shear of the other press parts sustaining and transmitting the driving force, a safety feature is provided. When a resistance is encountered by the slide, of such magnitude that the press frame l2 would be excessively strained or broken, the bolts M will yield beforehand, and thereby save the press from such an excessive strain. Likewise the crank ll, pins 30, 34 and 36 will be safeguarded against strains which would cause these pins to shear.

The arms 21 and 32 of the rocker 2| are set at a suitable angle to one another, such, for example, as that illustrated in the drawings. As shown in the drawings, the arm 32 is at an angle of 30 from the center line CL of the slide; which passes through the centers of the journal 35 and pin 30, and the arm 32 swings an equal distance on each side of said center line, its arc of swing being bisected by said center line. Said arm 32 may swing at a greater angle than said 30. Good angles are obtained throughout the working of the parts of. the slide driving mechanism through an angle of 90 of movement of said arm 32, 45 on each side of said center line of the slide. The throw of the crank I? is related to the angularity of the arms of the rocker E l. The throw of crank I! (that is, the diameter of its crank circle) is equal to the length of the chord of the are through which the arm 3-2 moves, said are being measured at the center of pin 39. With the arm 32 set at an angle of 30 to the slide center line, the arm swingsthrough an angle of 60, and the length of the chord of said are of 60 equals the throw of the crank ll. By such an arrangement the slide M will be moved to its bottom-of-thestroke position, with the rocker 2| in the position shown in Fig. 1, when the crank is in one of its dead center positions, and driving force on the working stroke of the slide will be transmitted under compression from the crank to the driving rod. When the rock r 25 is reversed, as shown in Fig. 3, the slide i will also be at the bottomof-the-stroke position when the crank is at its opposite dead center position, and the driving force of the crank I! will be transmitted on the working stroke of the slide under tension to the driving rod I9. The center of the crank shaft it is at a height which approximates the height of the chord of the are through which the arm 32 moves. As shown, the center of crank shaft 95 is about midway between said chord and the center of the journals 35, for the purpose of better stabilizing the weight at the top of the press.

The rocker 2| may be finished by the press manufacturer except for boring the hole through which the pin as passes. When the press manufacturer receives an order for a press having a specified stroke, he can bore the hole for the pin 39 at the proper distance from the center of the journal 38 to give the specified stroke. In Fig. 4 two holes s5 and 46 are indicated with dotted lines, a shorter stroke being imparted to the slide 14 when the pin connecting arm 2? to the con necting rod 23 passes through the hole 35, and a longer stroke being imparted to the slide it when the aforesaid pin 38 passes through the hole 56 in the said arm 27.

Operation Driving force is imparted to the crank shaft 16 through the fly wheel 25, or by other suitable means. The crank I1, as it rotates, oscillates the rocker 21 on its journals 35, and the rocker, through the connecting rod 23, reciprocates the slide it toward and from the bed. At the dead center position c-l of crank ii, the arm 32 of the rocker 2! is moved to one end of its arc of movement, and the arm 27 of the rocker is moved into alinement with the connecting rod and slide. That is, the centers of journals 36, pin 33 and ball 38 are in alinement, and the press slide it is at its bottom-of-the-stroke position. As the crank l'l moves to its opposite dead center position c2, the arm 32 of the rocker is moved to its opposite extreme position, and the slide it is raised to its uppermost position through the rocker arm 2? and the connecting rod 23. In this arrangement, driving force is applied under compression to the driving rod 19.

When it is desired to apply driving force under tension to the driving rod E9, the position of the rocker 2i is reversed. That is, the rocker 2| is turned around so that when the crank I? is in its dead center position c-i, the slide is at its uppermost position, instead of at its bottom-ofthe-stroke position, as in the arrangement prior to the reversal of the position of the rocker 2|. In the reversed arrangement of rocker 2i the slide is moved to its bottom-of-the-stroke position when crank 17 is in its dead center position c2, and in this position, and approaching it, driving force is applied under tension to the driving rod it by crank I].

There is imparted by the mechanism described a slow end movement to the slide it on its working stroke, and there is this slow end movement of the slide on its approach to its bottcm-of-thestroke position with the rocker either in a given position, or in a position the reverse thereof.

The movement of the slide I 4 through a crank cycle is similar to that of the slide in a knucklejoint type of press. There is an advantage over the knuckle-joint type of press with the present construction, inasmuch as there is a firm and positive connection of the slide with the slide actuating mechanism, and thus the slide, on its return-stroke, is able to pull out of, or be stripped from, work which clings tightly to the punch or other tool carried by the slide. There is also the further advantage that through the use of the adjustable connecting rod, adjustments of much greater magnitude can be made of the bottom-ofthe-stroke position of the slide than with the slide of an ordinary knuckle-joint type press.

In Fig. 6 the movement of the slide through one crank cycle is illustrated by the curve X. The curve designated by the letter Y is a curve for the movement of the slide through one crank cycle of an ordinary crank-press. The slow endmovement of the slide, as it approaches its hottom-of-the-stroke position, clearly appears when curve X is compared with curve Y.

What is claimed is:

l. A mechanical power press, consisting of a crankshaft having a crank thereon, a reciprocatory slide having means for mounting a forming tool directly thereon, and means for reciprocating said slide consisting of a rocker pivotally mounted in alinement with said slide, a connecting rod pivotally connected at one end to said slide and at its other end to one arm of said rocker, and a driving-rod connected at one end to said crank and at its other end to a second arm of said rocker, the longitudinal axis of said connectingrod intersecting the axis on which said rocker turns, and the longitudinal axis of said driving at one of its dead center positions in one position 10 of said rocker and at its opposite dead center position in the reversed position of said rocker, both coincidental with the position of said slide at its bottom-of-the-stroke position.

WILLIAM KLOCKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 143,292 McGowan et a1. Sept. 30, 1873 224,602 Parker Feb. 1'7, 1880 285,083 Stevens Sept. 18, 1883 1,749,334 Georg Mar. 4, 1930 2,027,735 Klocke Jan. 14, 1936 2,124,965 Lind July 26, 1938 2,161,869 Klocke June 13, 1939 

